That starts with a bonus 12-race card at Forbury Park tomorrow night as well as the two-day Marlborough meetings on the weekend likely to provide at least a handful of wins.
So setting a new record now looks near certain and if (when) Dunn does, it will come as a double achievement as that 221st win would also be his 2000th in New Zealand, joining a club with four other members.
Meanwhile, one of the first really major races Dunn ever won, the Victoria Cup, has undergone a controversial change.
The group one, won by Lazarus this season, will move from being the cornerstone of the Victorian summer carnival in late January to October 14, having its stake halved to A$200,000 in the process.
Harness Racing Victoria rightly believe having the Victoria and Hunter Cups a week apart during the summer carnival caused them to cannibalise each other, with most of the really big names starting in only one.
So the Hunter Cup will now be clearly Victoria's biggest race, expected to still be worth around A$500,000.
But the Victoria Cup could struggle to attract the absolute glamour pacers from New Zealand because it will be less than a month before the New Zealand Cup.
One big-time Grand Circuit player who won't be at either carnival is Bling It On, with this season's Hunter Cup winner suffering a horror fall in Brisbane on Saturday night.
He was rushed to a vet clinic needing surgery after cutting both front legs and getting grit from the track in the wounds.
"Hopefully he will be all right, if he doesn't get an infection, but I doubt you will see him racing again this year," driver Luke McCarthy told the Herald.